1. Field of the Invention
The present invention relates to a screw decanter type centrifugal concentrating machine and more particularly to an improved screw decanter type centrifugal concentrating machine for continuously treating so-called suspension containing fine solid particles in liquid with the aid of centrifugal force to separate it into concentrated liquid containing a high content of solid particles and residual liquid containing no solid particle or a very small amount of solid particles.
2. Description of the Prior Art
A hitherto known screw decanter type centrifugal concentrating machine is generally constructed such that a required number of nozzles of which bore is selectively determined are disposed at the position located in the vicinity of a deposition area at the one end of a bowl where solid particles conveyed by a screw are deposited so as to discharge deposited solid particles through the nozzles which are usually located on a side wall 3 as illustrated in FIG. 1. However, it has been pointed out as drawbacks inherent to the conventional centrifugal concentrating machine that it is possible to change a discharge rate of liquid through nozzles during operation of the machine and moreover carry out immediate adjustment in response to fluctuation in supply rate of suspension, concentration of solid particles or the like and that there is necessity for interrupting operation of the machine at every time when there occurs such a trouble that nozzles are clogged with foreign material. Another drawbacks of the conventional machine are loss in kinematic energy due to discharging of concentrated liquid and residual liquid from the circum-ference of the bowl, power loss due to blower function and air resistance caused by projections and openings for the arrangement of nozzles and liquid level adjustment during rotation of the bowl and power loss due to scattering of flowing air through openings on the outer casing of the bowl.